EnBW ZNL Esslingen

Case study

With the central control room (ZNL) in Esslingen, the EnBW Regional AG technology center meets the requirements for a safe and efficient network management of the medium voltage power distribution. Twenty highly qualified operators ensure smooth power distribution functions at any time - in Stuttgart, in the central Neckar area and up to the northern Black Forest. With the latest technology, approximately 15,000 transformer substations, 200 substations and 10,000 kilometers of medium voltage overhead power lines and cable are controlled.

Network control and monitoring – around the clock
One of the most important tasks of the control center is the continuous monitoring of the networks and their control. This process is carried out by two procedures. The strategy is to "control centrally – act locally", therefore the 4,000 square kilometers area is controlled from the central control room ZNL, while field crews carry out the work. The ZNL monitors and controls the current power flow as well as the voltage in the distribution network.

Overloads and limit violations are immediately corrected by appropriate measures, such as reconfiguring the network. Network calculations, simulations and interlocking functions support the operators in controlling the network. All operators working in the ZNL have many years of experience, and undergo regular training to keep their knowledge up to date.

Immediate troubleshooting & disturbance recovery
The network control center is like a spider's web - all information is gathered there. If the power fails at any location, fast fault detection, isolation and service restoration is essential. Today's technology helps to visualize the sometimes complex scenarios. The error location, which has been identified by the control system, is clearly visualized. The defective equipment is isolated from the healthy network either by remote control or by field crews working under instruction of the control center.

Tandem workplaces
The distribution management center consists of four control rooms. Each one is responsible for a part of the 10-, 20- and 30-kV medium voltage network. The four control rooms share a single control system, therefore any location can be controlled out of any control room. The operators are using so called "Tandem workplaces". Depending on the situation the operators can work individually or support each other. Each Tandem workplace is equipped with a Barco 4x2 OverView mDG50-DL rear projection system. The entire grid can be represented using either a schematic or a geospatial display that includes the map information. All important data are displayed: the locations of the transformer stations and substations as well as the power lines.

Overview – visualization of entire grid area
The video wall is connected to and shared by two operator workplaces, allowing simultaneous access of the video wall and maximum return on investment. The overview of the network together with the functionality of the control system supports the users in exceptional situations, e.g.

when there is a fault. The integration of the video wall into the 24/7 operations requires high availability. The dual lamp system, which is installed in the display walls of the distribution management system provides redundancy at the weakest spot - the lamps. A lamp failure will not result in a loss of image.